1+1/2对转涡轮低压动叶激波结构的研究

本文对1 1／2对转涡轮低压动叶中激波结构等进行了详细的数值模拟．通过对流道中静压和马赫数等参数的分析发现,当高压动叶外伸波扫过低压动叶流道时,低压动叶前缘吸力面处产生了一道脱体弧形激波,流道中吸力面上产生了一道正激波,在脱体激波和正激波之间,存在着较强的膨胀波,这种分布与跨音压气机叶栅中的波系结构相似．当高压动叶尾迹扫过低压动叶时,低压动叶吸力面的压力会产生明显的波动,出现一个随时间变化的低压区．

NUMERICAL SIMULATION OF SHOCK SYSTEMS OF LOW PRESSURE TURBINE IN VANELESS COUNTER-ROTATING TURBINE

A detailed unsteady numerical simulation has been carried out to investigate the shock and unsteady flow in the low pressure (LP) rotor in a 1 1/2 counter-rotating turbine (vaneless counterrotating turbine (VCRT)). Through analyzing the distribution of static pressure and Mach number etc. in the VCRT, it can be found that, when the outer-extending shock of high pressure (HP) moving from one LP rotor leading edge to the next, a bow shock appears upstream of the LP rotor, and a normal shock produces at roughly 70% axial chord on the suction surface of LP rotor, and between the bow shock and normal shock, a group of expansion waves exist. This distribution of shock in the VCRT LP rotor is similar to that in a compressor double-circular-arc (DCA) airfoil cascade at the same inflow condition, but in VCRT LP rotor, the shocks are confined to the suction surface side of passage and its intensity weaker. When the wake of HP rotor sweeps the LP rotor, the static pressure on the suction surface of LP rotor will fluctuate.